(1) Field of the Invention
The present invention relates to a method for repairing a display device and an apparatus for the same, and in particular, to a technology for repairing a display device using a plasma jet generated under atmospheric pressure so that a short-circuited portion or an open portion of the electrical circuit pattern on the substrate becomes normal.
In addition, the present invention also relates to a manufacturing method according to which a film can be locally formed or a surface locally processed, as well as a manufacturing apparatus for the same, and in particular, to a technology for local film formation or surface processing with a gas flowing through a reaction chamber.
(2) Related Art Statement
Liquid crystal display devices have a structure where liquid crystal is sandwiched between a pair of substrates where a color filter is formed on one substrate (sometimes referred to as filter substrate) by alternately applying blue, green and red resins, and an electronic circuit pattern including thin film transistors (TFT's) is formed on the other substrate (sometimes referred to as TFT substrate).
When there is a defect in the pattern of the color filter or a wire, the display of the liquid crystal display device becomes abnormal, and thus the product is inferior. Display abnormalities include color defects caused by the resin applied on the color filter sticking out over an adjoining pixel, unevenness in the color caused by inconsistency in the film thickness of the resins or the TFT substrate, short-circuiting and disconnection of wires and the like.
In methods for detecting such pattern defects, a general pattern inspecting apparatus which takes an image of the circuit pattern using an appearance inspecting apparatus and carries out an image process so that defects can be detected can be used.
As a method for repairing color filters where the color resins stick out over adjoining pixels or a wire has short-circuited, a repairing method according to which the short-circuited portion is irradiated with a laser beam and removed is generally used, as disclosed in Japanese Unexamined Patent Publication H9 (1997)-307217 (Reference 1), for example.
As a method for repairing a wire by filling in a missing portion with an appropriate material, there is a method for applying a wire material using a pipette with a finely pointed end, as disclosed in Japanese Unexamined Patent Publication H8 (1996)-66652 (Reference 2), for example. In addition, methods for depositing a metal thin film, referred to as laser CVD methods, according to which a desired region of a circuit substrate can be supplied with a material gas for a metal wire and irradiated with a laser beam so that the material gas decomposes are disclosed in Japanese Unexamined Patent Publication H7 (1995)-484967 (Reference 3) and Japanese Unexamined Patent Publication H11 (1999)-61413 (Reference 4) for example.
Liquid crystal display elements have a structure where liquid crystal is sandwiched between a TFT substrate where a circuit is formed on a glass substrate and a color filter substrate. When there is a defect on the circuit or the color filter, the liquid crystal display element has abnormal display, and thus becomes a defective product. The glass substrates used during the manufacturing process are becoming larger year by year, and it has become difficult to manufacture liquid crystal display elements having no defects simply by improving the process, and therefore, technology for repairing defective portions has become indispensable.
As a conventional method for repairing a circuit having a defect caused by a missing portion, a repairing method for locally forming a metal or insulating film so as to fill in the defective portion on the substrate using a laser CVD apparatus, a microplasma generating apparatus or the like can be used. In laser CVD apparatuses, a substrate is irradiated with a laser beam in a material gas atmosphere, so that the reaction of the material can be accelerated in the irradiated portion and a film is formed. In addition, in microplasma generating apparatuses, a material gas is introduced into a reaction chamber where microplasma is generated, so that the plasma accelerates the reaction of the material gas and a film is formed. In either apparatus, a technology for collecting the material gas so that it can be prevented from leaking out is necessary. In addition, a technology for preventing outside air from flowing into the reaction chamber is necessary, because the quality of the film deteriorates when air mixes in with the material gas.
With glass substrates increasing in size, the length of the side of some substrates may be more than 2 meters. Therefore, when the substrate is entirely surrounded by a chamber, the apparatus becomes very large, and problems arise, such that it takes time to replace the air within the chamber with an inert gas, such as argon, and in addition, the cost of the inert gas is high. Thus, a method for forming a film according to which a local gas sucking and discharging mechanism is attached is used, as in Japanese Translation of International Unexamined Patent Publication H1 (1989)-502149 (Reference 5), in the case where a film is locally formed in a laser CVD apparatus or microplasma generating apparatus. When a local gas sucking and discharging mechanism is used, only the reaction region is covered with a reaction chamber so that an inert atmosphere is provided, and therefore, it becomes unnecessary for the chamber to be large, and the time required for replacement with an inert gas can be shortened.
Local gas sucking and discharging mechanisms have a structure where a number of shells overlap in such a manner that the innermost shell provides a reaction chamber into which a material gas and a gas for generating plasma are introduced, so that a film can be formed or a surface process carried out, and gas that leaks out from the reaction chamber is sucked into the shell directly outside the innermost shell. One side of the shells is open, and the side with openings is located at a certain distance from the substrate on which a film is formed or a surface process carried out. It is necessary to keep the concentration and pressure of the material gas or gas for generating plasma supplied into the reaction chamber constant, and therefore, a new gas can be constantly supplied into the reaction chamber so as to replace the reacted gas. Accordingly, it is important to stabilize the flow of the discharged gas, so that the reacted gas can be smoothly discharged.
Japanese Unexamined Patent Publication 2003-51490 (Reference 6) discloses a plasma processing apparatus having a different structure from that described above. This plasma processing apparatus is provided with an opening for discharging the process gas that has been converted to plasma in the plasma generating portion toward a substrate, an opening for discharging exhaust provided at an appropriate distance from the opening for discharging the process gas, a gas discharging means for discharging waste gas through the opening for discharging exhaust after processing, a labyrinth sealing portion provided around the outer periphery of the plasma generating portion, and an inert gas supplying means for supplying an inert gas between the labyrinth sealing portion and the substrate. This plasma generating portion is provided so as to correspond to the width of the substrate (see FIG. 1), and the opening for discharging exhaust is in slit form and provided on the right side of the opening for discharging the process gas, which is also in slit form, so that the slits are parallel (see FIGS. 2 and 3), or openings for discharging exhaust in slit form may be provided on both sides (left and right) of the opening for discharging the process gas (see FIG. 7).